/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.rytong.tools.animation;

import android.view.animation.Animation;
import android.view.animation.Transformation;
import android.graphics.Camera;
import android.graphics.Matrix;

/**
 * An animation that rotates the view on the Y axis between two specified angles. This animation also adds a translation
 * on the Z axis (depth) to improve the effect.
 */
public class Rotate3dAnimation extends Animation {
    private final float mFromDegrees;
    private final float mToDegrees;
    private final float mCenterX;
    private final float mCenterY;
    private final float mDepthZ;
    private final boolean mReverse;
    private final String axis_;
    private Camera mCamera;

    /**
     * Creates a new 3D rotation on the Y axis. The rotation is defined by its start angle and its end angle. Both
     * angles are in degrees. The rotation is performed around a center point on the 2D space, definied by a pair of X
     * and Y coordinates, called centerX and centerY. When the animation starts, a translation on the Z axis (depth) is
     * performed. The length of the translation can be specified, as well as whether the translation should be reversed
     * in time.
     * 
     * @param fromDegrees
     *            the start angle of the 3D rotation
     * @param toDegrees
     *            the end angle of the 3D rotation
     * @param centerX
     *            the X center of the 3D rotation
     * @param centerY
     *            the Y center of the 3D rotation
     * @param reverse
     *            true if the translation should be reversed, false otherwise
     */
    public Rotate3dAnimation(float fromDegrees, float toDegrees, float centerX, float centerY, float depthZ,
            boolean reverse, String axis) {
        mFromDegrees = fromDegrees;
        mToDegrees = toDegrees;
        mCenterX = centerX;
        mCenterY = centerY;
        mDepthZ = depthZ;
        mReverse = reverse;
        axis_ = axis;
    }

    @Override
    public void initialize(int width, int height, int parentWidth, int parentHeight) {
        super.initialize(width, height, parentWidth, parentHeight);
        mCamera = new Camera();
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        final float fromDegrees = mFromDegrees;
        float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);

        final float centerX = mCenterX;
        final float centerY = mCenterY;
        final Camera camera = mCamera;

        final Matrix matrix = t.getMatrix();

        camera.save();
        if (mReverse) {
            camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
        } else {
            camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
        }
        if (axis_.equalsIgnoreCase("y"))
            camera.rotateY(degrees);
        else
            camera.rotateX(-degrees);

        camera.getMatrix(matrix);
        camera.restore();
        if (axis_.equalsIgnoreCase("y")) {
            matrix.preTranslate(-centerX, -centerY);
            matrix.postTranslate(centerX, centerY);
        } else {
            matrix.preTranslate(centerX, -centerY);
            matrix.postTranslate(centerX, centerY);
        }
    }
}
